Yesterday, Erin's husband, Steve Fleischmann, penned an emotional open letter to fans, explaining his late wife's last moments before her death, her unfortunate illness, and more. "She started radiation and chemo," he said, adding that he originally thought it was tonsillitis. "Five days a week radiation and chemo only on Thursdays. It got so bad so fast."

This comes after her co-star, Scott Baio, defended his previous comments that his Joanie Loves Chachi co-star may have passed away from a drug-related issue. “Please stop assuming the [worst] in me. I'm a compassionate person. I'm very heartbroken over her passing, especially since it was cancer,” he said.

Click through the gallery below to see the cast of Happy Days then and now.

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Ron Howard (Richie Cunningham)

Since Happy Day, Ron has moved behind the camera and now works as a director. He's helmed countless films including Splash, Apollo 13, How The Grinch Stole Christmas, and The Da Vinci Code.